Additional cardiovascular fitness when progressing from moderate- to high-intensity exercise training in previously trained breast cancer survivors.

Objective: Cardiovascular disease, often secondary to chemotherapy, is the leading cause of death in BC survivors. Increased aerobic capacity improves post-rehabilitation survival; however, many cancer rehabilitation programs are limited to lower intensity training. High-intensity interval training (HIIT) is associated with the largest improvements in aerobic capacity; therefore, this study aimed to determine whether HIIT would cause a greater increase in VO2peak than continuous moderate-intensity (MICT) exercise in previously trained BC survivors.

Methods: Twenty BC survivors who had completed a low/moderate-intensity exercise rehabilitation program performed a VO2peak test and received a dual-energy X-ray absorptiometry (DXA) scan at baseline and after randomization into a 12-week HIIT or MICT program. ANOVA with repeated measures determined the effects of the different training programs on aerobic capacity and body composition.

Results: Both groups began the training program near or above age- and sex-matched VO2peak norms. Pre- to post-intervention improvements in VO2peak (P = 0.006) and waist circumference (P = 0.007) were found in both groups; however, there were no between-group differences. Minute ventilation and peak workload increased in the HIIT group (P < 0.05) but not the MICT group. Body composition was not different after either training program.

Conclusions: These data suggest that transitioning from low/moderate-intensity exercise to moderate/high-intensity exercise causes further clinically relevant increases in VO2peak in previously trained BC survivors. HIIT did not cause a significantly greater improvement in VO2peak than MICT; however, future studies with greater intensity and frequency of training are encouraged.